Showing papers by "David Bacon published in 1975"
TL;DR: The static equilibrium configurations of a dislocation bypassing a periodic row of impenetrable circular obstacles were obtained for various crystals by means of a self-stress method wherein the elastic anisotropy of the crystal and the dislocation self-interaction could be taken into account.
Abstract: The static equilibrium configurations of a dislocation bypassing a periodic row of impenetrable circular obstacles were obtained for various crystals by means of a self-stress method wherein the elastic anisotropy of the crystal and the dislocation self-interaction could be taken into account. A correlation was developed from the results which related the Orowan stress values to the obstacle size and spacing. This correlation demands two parameters to account for the anisotropy, and these appear as a suitably defined anisotropic shear modulus and Poisson's ratio. The self-interactions are taken into account by a single logarithmic parameter which is the harmonic mean of the obstacle size and spacing, and is independent of anisotropy. The shapes of the bowing dislocation loops are strongly influenced by the anisotropy and interactions. The combined effects on shape can bo simply described in the line-tension framework, using the de Wit—Koehler solutions. In particular, the swept areas and overall ...
192 citations
TL;DR: In this paper, the defect-molecule calculations of Coulson et al. have been improved and extended to allow for symmetric relaxation in graphite, and the neutral vacancy formation energy has been re-calculated, and using the above values for Ev and ER a value of 8.75 eV was obtained.
11 citations
TL;DR: In this article, the lattice statics have been used to calculate the atomic displacements around a vacancy and the vacancy-vacancy interaction energy in graphite, and it is shown that the distortion of the graphite layer by a vacancy is not small, and the resulting relaxation energy is −3.3 eV.
Abstract: The method of lattice statics has been used to calculate the atomic displacements around a vacancy and the vacancy-vacancy interaction energy in graphite. This was achieved by simulating the vacancy by external forces acting radially on the nearest neighbour atoms, and calculating the lattice Green's function for a two-dimensional model of the graphite structure. Numerical values for the Green's function are presented, and the leading elastic and lattice terms in its asymptotic expansion are derived. Using a value of the external forces obtained from a molecular-orbital calculation, it is shown that the distortion of the graphite layer by a vacancy is not small, and the resulting relaxation energy is −3.3 eV. The formation area of a vacancy is −0.14 atomic areas, and the mechanical binding energy of a divacancy is 2.0 eV.
4 citations